Capsule making apparatus

ABSTRACT

An improvement in capsule making apparatus is provided in the form of air duct means for conditioning freshly dipped capsule mold pins at a point in the work cycle just prior to the elevation of the pin bars to the drier stage. The film coating on the pins is thereby stabilized so that asymmetric film flow during transfer and elevation is substantially decreased.

1 1 Feb. 26, 1974 United States Patent Padilla et a1.

CAPSULE MAKING APPARATUS Tingquist et a1. 425/270 X Inventors: SalvadorA. Padilla, 14819 Horger,

Allen Park, Mich. 4810]; Richard A. Curtis, 36400 Howard Rd.,Farmington, Mich. 48024 Aug. 2, 1972 Appl. No.: 277,396

Primary ExaminerRichard B. Lazarus Attorney, Agent, or Firm-Robert R.Adams [22] Filed:

ABSTRACT [52] US. [51] Int Cl [58] Field of Search425/269, 270, 385,324, 324 B;

[ 56] References Cited UNITED STATES PATENTS 1,114,325 10/1914Winchester............,........ 425/270 X 5 Claims, 5 Drawing FiguresCAPSULE MAKING APPARATUS SUMMARY AND DETAILED DESCRIPTION:

This invention relates to capsule making apparatus and more particularlyto an improvement in means for .movement through drying kilns until thefilm has solidified. It has been considered essential in this operationto rotate the pin bars during elevation in order to maintain uniformdistribution of the liquid film on the pins. Nevertheless, the practiceoften results in a nonuniform thickness in the capsule shell wall,particularly in the so-called shoulder area. It is found, for example,that the shoulder wall on the leading side of the pin in the directionof the rotation is usually thin whereas on the trailing side it isrelatively thick.

It is therefore an object of the present invention to provide improvedmeans for handling freshly dipped capsule mold pins.

It is also an object of the invention to provide economical means formaking capsules having improved wall thickness characteristics.

It is a further object of the invention to provide means for maintaininga balanced radial distribution of film in the production of dip-moldedcapsules, particularly in the shoulder area.

v These and other objects, features and purposes of the invention willbe seen from the following description in relation to the accompanyingdrawing in which:

FIG. I is an elevational view partly in section of capsule makingapparatus including a dipping tank, elevator and air duct system;

FIG. 2 is a view of the air duct of FIG. 1;

FIG. 3 is a fragmented view of an air duct; and

FIGS. 4 and 5 are enlarged views of coated mold pins in the pin down andpin up positions, respectively.

Referring to FIG. 1, the dipping tank which may be conventional in formincludes a dipping dish 11 surrounded by a reservoir 12 containingdipping solution 13 in a constant temperature jacket 14. Capsule pinsmounted on bars 21 are located, as illustrated, at successive workstations of the operation: at the dipping station A, at the base orloading station B of an elevator 30, at the unloading station C (dottedoutline), and at a platform which is the starting run D through a seriesof driers. Mechanical finger means (not shown) are provided inconnection with'each dipping cycle for engaging and sliding the pin barset at A along a guide track 22 into the loading station B of theelevator. The elevator has a pair of vertical racks 31 which cooperatewith a like pair of pinion gears 32 and discs 33. The two discs eachhave a groove 34 and are spaced in the loading position illustrated,with the grooves in alignment with the top surface of the guide track22, to receive the opposite ends of each advancing pin bar for loading.Surrounding the elevator disc 33 is a flanged retainer ring 35 whichremains stationary with respect to the disc and thus serves to retainthe pin bars within the groove as the disc rotates while moving upwardlyon the rack. The gear and rack combination is arranged for movement ofthe elevator to the upper terminal position C illustrated in dottedoutline at which the elevated pin bars stand in the pin up position fortransfer from the groove 34 to the platform 40. In accordance with apreferred embodiment of the invention shown in FIGS. 1 and 2, an airduct or conduit is provided having an open outlet 51 located below theloading position B. The air duct'communicates with a suitable source(not shown) of clean air under positive pressure at room temperature orlower temperature. As shown, the air duct outlet 51 is sufficientlylarge to surround the array of pin ends 20a of bars at the loadingstation. In this regard, the end of the conduit 50 may have an outwardflare 52 to favor a greater outward flow of air around the perimeter ofthe array of pins.

The embodiment shown in FIG. 2 features distribution baffles 53 and ascreen tray 54 which insure uniform air flow across the opening 51through the confined zone surrounding the pin ends 20a at the loadingstation. The screen tray preferably fits the outlet opening closely andis removable for cleaning purposes.

is rectilinear and extends around each array of pins standing at theloading position B provides for intake of atmospheric air through theconfined zone surrounding the ends of pins so located. Opening 51bserves to provide clearance for unloading the bars 21 from station C tothe platform 40.

OPERATION In a typical operation, the pins 20 are dipped in gelsolution, withdrawn, exposed to air flow and transferred to the loadingstation B, elevated with rotation, transferred to the drier, dried,stripped, and greased (in preparation for the next cycle). For dipping,the solution which may be an aqueous gelatin solution is maintained at asuitable temperature, conveniently in the range'from about ll0-l15 F.The pins are dipped five bars at a time at the rate 0E0 bars per minute.The time required for dipping, loading, and elevation and transfer tothe drying platform 40 is about 15 seconds. Transfer to the elevator(position A to position B) requires less than one second, followingwhich the pin bar sets come to a dead stop. In accordance with theinvention, air is delivered through the orifice 51 (or 51a, FIG. 3)under conditions such as to cool and stabilize the film coating on thepins, for example at room temperature or lower under controlledhumidity, preferably 50 percent or lower, and at a linear flow rate ofabout 5 feet per second. The air-flow conveniently is continuous so thatthe pins are exposed to the same during the transfer to position B andduring the dead stop and elevation. Substantially all of thefilmstabilizing effect takes place during the transfer and dead stop.Thereafter the elevator is activated in conventional manner and theloaded pin bar sets are rotated to the terminal position C adjacent thedrier platform 40. While being elevated the pins are rotated (standardrotation is two and one-half times) from the pin down position tothe'pinup position illustrated in dotted outline. Following a short dwell time,the pin sets are transferred to the drier platform 40 and are thenprocessed through the remainder of the cycle in conventional fashion.

In the described loading and elevation by conventional means theindividual pins undergo linear and radial acceleration which it is founddeforms the wet film coating. FIG. 4 illustrates the deformation of thefilm coating 22a shown in dotted outline as the pin 20 is being rotatedfrom the load position and elevated. By comparison, according to thepresent invention, the film coating 22b shown in solid outline istypical of the air treated coating during the same phase of rotation.Advantageously, the film coating at the shoulder line 20b remainssubstantially uniform. Similarly, FIG. 5 illustrates the configurationof the coating of the fully elevated pin. The dotted outline 22billustrates the coating profile as the pin first arrives at position C.The solid outline 22c illustrates the profile of the finished film driedon the pin. Thus, prior to the drying step the film coating at the end20a of the pin is relatively thick. However, with progressive drying thecoating evenly redistributes itself axially upon the surface of the pinto provide a generally uniform thickness.

A critical measure of quality of molded capsules concerns the variationin wall thickness at the shoulder line 20b. Ideally, the wall thicknessin a given capsule should be constant throughout the shoulder line.Also, the wall should be relatively thick at the shoulder. To illustratethe advantage obtained by the present invention in this respect, thefollowing tables provide a comparison of values for minimum and maximumwall thickness at the shoulder line in capsules produced according tothe present invention and control capsules produced by conventionalmeans.

TABLE I Capsule Wall Thickness at Shoulder (MIN.)

Capsules Produced with Prc-elevation ii 4.8 23.5 4.6 l2 5.] l5.7 4.7 l25.2 5 4.8 8 5.3 7.8 5.0 8 5.4 3.9 5.4 8 5.5 3.9 5.5 4 5.7 3.9 5.7.Average, 4.99 mils Average, 4.60 mil Standard deviation, 0.38 Standarddeviation, 0.38

These results show that the capsules produced according to the presentinvention with respect to shoulder wall were superior to controlcapsules both as to thickness and variation in thickness.

While the invention in capsule making apparatus has been described inthe foregoing description in considerable detail, it will be realized bythose skilled in the art that wide variation of such detail can be madewithout departing from the scope of the present invention as claimed inthe following claims.

We claim: a

1. In capsule making apparatus comprising a set of capsule pin barshaving elongated pins each pin having a rounded end, a dipping tank, andmeans for transferring the pin bars continuously in timed relationthrough a stepwise cycle of pin dipping in gel solution, withdrawing andinverting the pins while coated with liquid film which is subject touneven distribution during transfer under action of gravity, and dryingand stripping the coating on the pins, the transfer means including anelevator for lifting and rotating pin bars from a loading station andmeans for supplying the loading station with bars of freshly dipped pinswith the rounde end of each pin lowermost,

the improvement characterized by air conduit means having a distributionorifice located adjacent the loading station for moving cooling airupwardly against the rounded ends of the coated pins, the orifice beingshaped to provide for uniform flow through a confined zone surroundingthe array-of pin ends of bars at the loading station.

2. Apparatus according to claim 1 where the distribution orifice islocated below the loading station and the air conduit means is incommunication with a source of positive air pressure.

3. Apparatus according to claim 1 wherein the distribution orifice islocated above the loading station and the air conduit means is incommunication with a source of negative air pressure.

4. Apparatus according to claim 1 wherein the air conduit means is incommunication with a source of air pressure adapted to generate air flowthrough the confined zone at a rate sufficient to stabilize the liquidfilm coating on coated pins located at the loading station.

5. Apparatus according to claim 3 wherein the air conduit meanscomprises a chamber surrounding the elevator.

1. In capsule making apparatus comprising a set of capsule pin barshaving elongated pins each pin having a rounded end, a dipping tank, andmeans for transferring the pin bars continuously in timed relationthrough a stepwise cycle of pin dipping in gel solution, withdrawing andinverTing the pins while coated with liquid film which is subject touneven distribution during transfer under action of gravity, and dryingand stripping the coating on the pins, the transfer means including anelevator for lifting and rotating pin bars from a loading station andmeans for supplying the loading station with bars of freshly dipped pinswith the rounded end of each pin lowermost, the improvementcharacterized by air conduit means having a distribution orifice locatedadjacent the loading station for moving cooling air upwardly against therounded ends of the coated pins, the orifice being shaped to provide foruniform flow through a confined zone surrounding the array of pin endsof bars at the loading station.
 2. Apparatus according to claim 1 wherethe distribution orifice is located below the loading station and theair conduit means is in communication with a source of positive airpressure.
 3. Apparatus according to claim 1 wherein the distributionorifice is located above the loading station and the air conduit meansis in communication with a source of negative air pressure.
 4. Apparatusaccording to claim 1 wherein the air conduit means is in communicationwith a source of air pressure adapted to generate air flow through theconfined zone at a rate sufficient to stabilize the liquid film coatingon coated pins located at the loading station.
 5. Apparatus according toclaim 3 wherein the air conduit means comprises a chamber surroundingthe elevator.